Most rewarding careers?

To my loyal readers,

I want to take a break from the usual blog topics and talk about something a little more personal.  For those who don't know, I am an economist working in the public service but find the work most frustrating, intellectually dull, and completely unchallenging.  You may say that this is no surprise, and that I really should have been expecting this situation.  But the pay and conditions are great and these things were very important when I started the job.

I am now contemplating my next career move and am seeking some advice.  My next move should meet the following criteria:
1.  Intellectual challenge
2.  Rewarding - in the way that you feel like you accomplished something at the end of the day
3.  Potentially ourdoors and active

Another idea is to simply sell up the traditional life, buy a sail boat, and take the family around the world - picking up some unskilled work as we go. If not now, when?

I would really appreciate any thoughts and ideas, no matter how 'out there' they are.

Cam

----UPDATE-----
I think the results of this online personality test sum things up, but don't know where that leaves me as far as a rewarding careers goes.

As a Groundbreaking Thinker, you are one of the extroverted personality types. Dealing with others, communication, discussions, and a little action are your life’s blood - and some of your strengths. You are very articulate and love variety personally as well professionally. New tasks, new projects, new people, fascinate you because you are always interested to increase your wealth of experience. Consequently, you have no problem dancing at several weddings; juggling parallel tasks to be accomplished electrifies you, and you are an accomplished improviser.

Your enthusiasm carries others along and enables you to create positive impulses in your team. Mountains of paperwork, endless e-mail correspondences, and solitary work tire you quickly, and bore and frustrate you. The appreciation of your work by others is more important for you than for the introverted Thinker types. You measure your own professional value by the admiring glances of your colleagues and superiors.

The psychologist Keirsey once described the Groundbreaking Thinker as the “soul of the company,” and that can be just as easily applied to an employee position, as to an independent chief of a company. Since risk represents less of a threat than excitement, freelance or self-employment are well suited to you. However, you must take care to have collaborating staff around you, or that you are able to work closely with other teams in order to satisfy your contact and communication needs. You are naturally suited for leadership positions because there you have the ultimate freedom making your decisions and choosing your tasks.

As a superior, you like to let your subordinates operate on a long leash as long as they do a good job, because it is not your thing to exercise power for power’s sake. Additionally, you don’t feel like worrying about the stuff of others. You much prefer that the person concerned disappears after you have handed him his/her task and later shows up with the finished (and naturally excellent) result. Based on your open way to communicate, then you are not parsimonious with praise.

If you are an employee, you should make sure that your company’s hierarchal structures are as level as possible because you have real trouble with authority for authority’s sake. Otherwise, you can handle critique or diverging opinions pretty well because you don’t take them personally, and are prepared to adapt if you can be convinced of the validity of an argument - if in your opinion it is “logical“.